Prismatic ornamentation



Get 9, 1956 2,765,556

'5. GERSHON PRISMATIC ORNAMENTATION Filed Jan. 25, 1954 3 Sheets-Sheet l IN VEN TOR.

Oct! 1956 B. GERSHON PRISMATIC ORNAMENTATION 3 Sheets-Sheet 2 Filed Jan. 25, 1954 INVENTO201Z e22 lzflzz'iL 02,5 16; Q5

Ilnited States Patent 2,765,556 PRISMATIC ORNAMENTATION Benjamin Gershon, Chicago, Ill.

Application January 25, 1954, Serial No. 405,937

3 Claims. (Cl. 4119) My invention relates to ornamentation, and includes among its objects and advantages an improved surface for manufactured articles, presenting patterned areas that are substantially mirror-like and shiny, alternating with areas that appear substantially non-reflective, at least to the naked eye; together with a cheap and expeditious method and apparatus for producing such surfaces in a wide variety of predetermined patterns and degrees of contrast.

In the accompanying drawings:

Figure l is a plan view of a machine for producing patterned surfaces on a conventional table mat, having a shiny top surface of metal;

Figure 2 is a side elevation of the same machine;

Figure 3 is a section on line 3-3 of Figure 2;

Figure 4 is a fragmentary view, as in Figure 3, indicating means for making certain darkened areas darker along their edges than in the middle.

Figure 5 is a diagram of the action of a scoring point.

Figure 6 is a section on line 66 of Figure 5; and

Figure 7 is a section similar to Figure 6, indicating the .sort of surface convention before the invention.

Referring first to Figures 5 and 6, the stainless steel body 16 may be protected over predetermined areas by a mask 12, of much harder metal, cut to a predetermined pattern. The scoring point 14 is shown just as it leaves an exposed area, after having formed a groove 16 in the surface of the body 10. It will be noted that the bottom 18 of the groove 16 is below the level of the surrounding undisturbed surface of the body 10. On the farther side of the groove 16, as viewed in Figure 5, the metal rises above the level of the undisturbed surface, to a crest, or ridge, 20. Because the point 14 is drawn along so slowly that the heat generated by deforming the metal of the body can dissipate itself and prevent any material rise in temperature of the metal undergoing deformation, there has to be volumetric equality between the space occupied by the body before and after deformation. Therefore, an isolated groove 16 will have two ridges 20, and the ridges include a volume above the level of the undisturbed surface exactly equal to the volume of the groove 16 below that level.

When a large number of such scoring points, arranged at random, as in the case of the ends of a conventional wire brush, are simliarly drawn along, at such slow speed that no physical removal takes place, as by a gouging tool or the throwing of sparks; the same equality obtains between projections above and depressions below the undisturbed surface, but the local configurations can be very irregular and of wide variety. Figure 6 is much simpler than the configurations usually secured in practice, but the simplified illustration is used for clarity in explanation. There are nine grooves, 22-1, 22-2, 22-3, 22-4, 22-5, 22-6, 22-7, 22-8, and 22-9. The grooves are of a wide variety of widths and depths, but all of substantially the same approximate radius of curvature, corresponding to the convexity of the scoring point 14. There is also a short portion at 24 where the original surface has not been disturbed at all; and at either side of the scored area, or strip, undisturbed portions 26 remain in their original condition.

When the metal used is the stainless steel commonly employed for making the type of container commonly called a can, the surface 24 and 26 are substantially mirrorlike. The stripe, therefore, oflsets the adjacent areas to provide the ornamental appearance which is the object of the invention. In the area of the stripe, the sub-microscopic irregularity of the disturbed surface is such that only a minor fraction of the incident light is reflected, and because of the striations the light that is reflected is effectively scattered in all directions, so that the mirror action is totally absent. Furthermore, because the widths of the successive grooves 22-1 to 22-9, are highly irregular and in a random arrangement, there is no rainbow or prismatic effect produced, as there would be with an arrangement even approximating the regularity of a ruled diffraction grating.

It will be obvious that the relative movement of the points and body may be produced by moving either one with respect to the other. In Figures 1, 2 and 3, I have illustrated machinery for the semi-automatic practice of the process, in which the working stroke is secured by movement of the body, While the brush points are advanced by suitable cam means in a direction normal to the plane of the body, to press them against the body as it moves under the brush.

The best results obtained so far are with scoring points also of stainless steel, but very much harder than the annealed steel of the body 10, with the dimension D, indicated in Figure 5 as the diameter of the wire, twelve thousandths of an inch. Wire of this size, pressed against the face of the body only hard enough to achieve such a surface contour as that of Figure 6, need not necessarily have its working ends spherical to secure desirable results. Such variations in end form as result from merely cutting the wire into lengths and fastening the pieces together in brush form, only result in grooves of relatively not quite circular cross section, as viewed in Figure 6. This enhances, rather than detracts from, the desired ornamental eflect.

For a long time before the present invention, I have been aware of the practice of producing ornamental patterns by a wide variety of bufling operations. A typical procedure was with a rapidly rotating brush, or series of brushes, with bristles of varying size andhardness. To produce deformations of the order of magnitude called for by the invention, there was always at least one operation where sparks would fly, as the rotating brush attacked the surface to be conditioned. This means removal of material. Removal of material, per se, in the insignificant amounts involved, is not necessarily objectionable, but the final result was always substantially according to Figure 7, Where the area 28 has an average elevation a little below the surrounding undisturbed surface 30, and a fine saw-tooth contour that frequently produced iridescence, and Was anything but a flat area to offset the adjacent mirror-like surface. After produring such a surface as is indicated in Figure 7 it is always possible to go over the corrugated buffed area with finer and finer bufiing tools, and eventually with bufling tools softer than the metal itself. In this way, any gradation between the surface shown at 28 in Figure 3, and one substantially as smooth and mirror-like as the surrounding areas can be produced. But none of these gradations provide the flat, apparently unreflecting stripe indicated in Figure 6.

Furthermore, if a mask is used to get predetermined patterns, the rapidly acting bufiing tool tears the mask to pieces after only a few units have been processed, and even a single bufling involves prohibitive expense in replacement of masks and bufling wheels, compared with the process of the invention. In proceeding according to the invention, with a mask of metal about as hard as the scoring points, the life of the mask is almost indefinite, and each point develops a polished spot after a few trips over the mask, such that deformation of metal occurs only between the point and the body, and the friction between point and mask is small.

An interesting practical criterion of operation completely according to the invention, is the substantial absence of any accumulation of powder or dust. Microscopically, even at speeds that seem low from a microscopic point of view, tearing of the materials of the work piece begins to occur, and fine particles are detached from the work piece and accumulate as dust. Such an accumulation that seems to the naked eye to be merely fine powder, when examined under high magnification, reveals unexpected characteristics. A substantial fraction of such dust, will be found to be gobbets that show unmistakeable evidence of fusion. Such a gobbet may be approximately spherical and about two thousandths of an inch in diameter. Simple arithmetic shows that with a point 14 traveling at a speed of two feet per second, the time interval for the tool to travel the diameter of the gobbet, and detach and dislodge the gobbet, is only one twelve thousandth part of a second. It is also well known that the energy absorbed by a metal body when such a particle is torn out of it, is ample to heat the particle to incipient, and usually to complete fusion, for the tiny fraction of a second during which the violent disruption is going on. Hence, sparks.

Whatever the theory may be, the pragmatic fact is that with wire bristles of twelve thousandths inch in diameter, the speed for best results according to the invention in about one third of a foot per second. Lower speeds secure equally good results, but not noticeably better, and the lower speed merely reduces the hourly output of the equipment. What the upper speed limit may be, I am not at present in a position to state with certainty.

It will no doubt vary with the specific hardness and elastic limit of the surface layers of the material of the workpiece, and cold rolled material with the stresses of the cold rolling unrelieved can be expected to act differently on that account. With soft stainless steel for the work piece, and hard stainless steel for the bristles, and applied pressures light enough so that two passes are needed to generate striations approximating the configuration indicated in Figure 6, one third foot per second secures very good results, and a change to twice that speed materially alters the action and the results for the worse. At a speed of about three feet per second, the undarkened, slightly fogged appearance indicated in Figure 7 as the prior art practice with which I have long been familiar, is much closer to the result secured, than Figure 6 is.

It will be obvious that with non-ferrous metals of much greater plasticity, in which Youngs modulus and the percentage of elongation before rupture are materially different from the corresponding values for steel, the speeds and pressures may vary considerably, but the criteria explained above should enable anyone to make a few obvious tests to ascertain the optimum speed for any combination of materials.

Referring now to Figure 4, I have indicated a portion of the brush back 32, carrying bristles 34, having points 14 at their lower ends. The workpiece is shown at 10, and the mask above it, identified as a whole by the reference character 12, includes flat covering portions 36 and arched covering portions 38. It will be obvious that the flat portions 36, merely lift the points without deflecting them laterally, so that such a striated area as 44 will have approximately uniform density of striations across its width. On the other hand, the arched portions 33 work up between the bristles 34, so that there is a crowding of thepoints 14 along the side of each such arched portion.

Accordingly, the striated area 42 will have its right edge merely discontinued in line with the edge of the mask portion 36, but at its other edge it will be shaded darker because of the crowding of the bristles. Similarly, the area will have both edges darkened and a somewhat less dark zone down its middle. In this way it is possible to secure shading effects roughly approximating those of a wash drawing.

The details of the equipment for practicing the invention may be largely conventional. I have illustrated a machine in which the workpiece is traversed, and the brush is relatively stationary, with pressure applied by lowering the brush toward the work piece. The frame 46 has a track 48, and the carriage 50 has four wheels 52 rolling on the track 48. The mask 12 is in a frame pivoted on a transverse axis at 54, so that the mask can be swung clockwise about ninety degrees from the position of Figures 1 and 2, to permit the operator to lay the workpiece on the carriage and then lower the mask into working position. A simple pivoted latch 56 overlies an ear 58 on the mask frame, to hold the parts during the working stroke.

The motor 60 has a belt drive to the pulley 26 on the shaft 64. From the shaft 64, the chain 66 drives the sprocket 68 on the shaft 70. From the shaft 70, the chain 72 drives the sprocket 74 on the shaft 76. The shaft 76 carries a pinion 78 meshing with a rack 80 on the bottom of the carriage 50.

After the workpiece is in place and fastened, the operator energizes the motor by means of a switch located at 82 (see Figure 2), and the carriage moves to the right until it engages a mechanical stop 84 (see Figure l), which has an operating rod 86 extending back to the switch at 82, and reverses the motor. The workpiece and carirage now move back to the left, until they encounter the cut-out switch at 88, and the parts come to rest in position for the operator to remove the finished workpiece and put in another one.

Automatic means are provided wor lowering the brush into working position. Twin walking beam levers 90 (see Figure 3) are supported on fixed ivots at 92, on each side. The inner ends of the levers are connected to the brush frame 94 by short pitmans 96. The outer ends of the levers carry counterwcights 98, heavy enough so that the parts ordinarily rest with the brush elevated, but almost balanced, so that a small force will move it down. Side standards provide vertical guidance for heads 102, and each cross head has a lower contact wheel 104 (see Figure 2) positioned to ride on a strip cam on the carriage. The strip cam has a central plateau 106 (see Figure 2), and a front breast 108 and a rear breast 110. Each cross head carries a riser 112, adjustable by means of a nut 114. Each riser lies under the outer arm of its walking beam 90. It will be obvious that as the carriage moves across, the cross heads will rise, and the risers will push the outer ends of the walking beams 90 up, and force the pitmans 96 and brush 94 down.

Others may readily adapt the invention for use under various conditions of service, by employing one or more of the features of novelty involved, or equivalents thereof. As at present advised with respect to the apparent scope of my invention, I desire to claim the following:

1. The method of forming ornamental striations in the surface of a metal body having a mirror-like specular reflecting surface, which comprises pressing a large number of closely spaced rounded bristle scribing points resiliently against said surface; said points being of greater hardness than said body; and moving said points and body with respect to each other in a movement of rectilinear translation, with said points guided by their contact with said surface, across said surface slowly; by such movement scribing continuous elongated parallel grooves having smooth rounded, substantially arcuate bottoms; said points remaining stationary with respect to said body, ex-

cept for the scribing movement of translation.

2. A manufactured article of the type having a rigid sheet metal facing plate; said facing plate having an initially mirror-like specular reflecting surface; said surface presenting unaltered areas separated by straight striated marking bands; each marking band comprising a large number of continuous elongated shallow parallel grooves; each groove having a smooth and approximately arcuate bottom; whereby each band presents a frosted appearance with relatively little reduction in the fraction of the incident light reflected from its striated surface.

3. A manufactured article of the type having a rigid sheet metal facing plate; said facing plate having an initially mirror-like specular reflecting surface; said surface presenting unaltered areas separated by straight striated marking bands; each marking band comprising a large number of continuous elongated shallow parallel grooves; each groove having a smooth and approximately arcuate bottom; whereby each band presents a frosted appearance with relatively little reduction in the fraction of the incident light reflected from its striated surface; said facing plate having a plurality of ridges; each ridge lying at an angle to and intersecting a plurality of said marking bands; said marking bands, at their intersections with said ridges, continuing in substantially unaltered appearance up one side of the ridge and down the other side.

References Cited in the file of this patent UNITED STATES PATENTS 1,347,173 Mathes July 20, 1920 1,431,917 Antaramian Oct. 17, 1922 2,218,913 Hughes Oct. 22, 1940 2,617,223 McElroy Nov. 11, 1952 2,637,929 Hausman May 12, 1953 2,693,658 Nobis Nov. 9, 1954 

